1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method which are capable of correcting image data including defective pixels caused by manufacturing of a solid-state image pickup device.
2. Description of the Related Art
A solid-state image pickup device sometimes includes a defective element which is incapable of properly reacting to incident light, due to a manufacturing process of the image pickup device. It is difficult to manufacture a solid-state image pickup device completely free from such a defective element.
To overcome this problem with a conventional apparatus using a solid-state image pickup device, there has been proposed a unit for correcting data of a defective pixel (defective pixel data) output from a defective element of the solid-state image pickup device, using a one-dimensional or two-dimensional filter (see e.g. Japanese Patent Laid-Open Publication No. 2006-324908). The unit configured to use the filter to correct the defective pixel data performs correction using pixel data obtained from normal pixels (reference pixels) around the defective pixel which have information on the same color as that of the defective pixel data.
In the unit that performs correction using the filter, however, there arise a problem that when correction is to be performed on entire image data, if a defective pixel is located at an end of the image data, some of reference pixels which are to surround the defective pixel are missing, which makes it impossible to correct the defective pixel.
To solve this problem, there has been proposed a unit in which when some of reference pixels for filtering are missing, data at the end is extrapolated to a location where the missing reference pixels should exist, whereby pseudo reference pixels are generated so as to enable the use of the filter (see e.g. Japanese Patent Laid-Open Publication No. 2006-094160).
In the conventional correction unit for use when some of reference pixels for filtering are missing, however, it is required to generate pseudo reference pixels by copying effective pixel data at the end of image data so as to make up for missing reference pixels. The operation of copying effective pixel data to generate pseudo reference pixels for missing reference pixels has to be performed by suspending the input of image data. This degrades throughput of the image processing apparatus. Further, the correction unit requires flow control for stopping image data input and a control circuit associated with the flow control, and therefore circuitry becomes complicated.